Worked perfectly on my 2010 w204... move the lmax volume level under the sound / entertainment menu all the way upto 85... Now to add a flat sub and upgrade the fronts... The question is JL-TW5 or Rockford Fosgate P3S-12 but dont know what to do for the fronts.

I am amazed at the sound quality between this and the Comand HK sound I have in my ML... Especially via the iPod interface....

As for a sub, neither of those you mention are really efficient (less than 86 dB for 1 watt), go for something like the Polk Audio MM 1040, its cheaper and almost 6 dB more efficient (needs 25% the amplifier power of your choices).

The options in this secret menu, do not "raise" your maximum volume, only balance various inputs to make the outputs more equal. The maximum volume is determined by the performance of the output amplifier section (only Audio 20 here, not HK as NewtwoMB comments), which has a limiter. For your experimentation, you can play the radio or a CD, and keep turning up the volume with the front round volume knob - after a certain point turning the knob provides no increase in volume, the amp has reached its limit. Its well done actually, as it limits when the amps output reaches a predetermined distortion, sounds like 10% THD. Those who like it "as loud as it gets" should turn the volume knob (or steering wheel controls) up until the volume stops increasing, then back it off a bit to reduce the distortion without reducing the maximum volume.
Several posts complain about LOW volume. Why is it LOW? It is only the iPod? Is it the Aux? Is it the Bluetooth? If you can be more specific, some solutions could be posted as it sounds lie the problem cannot be solved changing the preestablished settings in this secret menu. Low volume from the iPod in particular (and bad EQ) has several causes, if the problem can be described, solutions will be posted.

Bill,
How can I balance out the volume amongst the various inputs so that I don't have to change volume while switching from ipod to radio to cd, etc (I have Audio 20)? Currently, the ipod level is lower.
Thx,
B

This weekend there is some time for checking if the Radio and CD can be balanced. The iPod has several options, however three questions:
1.- Is the iPod connected through the AUX or through a MB iPod Interface?
2.- If you have the Interface, is there an iPod Amplifier attached?
3.- If you have the iPod amplifier, is it from Germany or China?

Several preliminary comments are necessary here:
1.- Volume between the radio and CD - this should be preset at a "0" point (i.e. maximum radio voltage output equal to maximum CD output at +6). Radio voltage output on an average signal doesnt vary much in FM, this can vary in AM of course. Tje problem here is that CDs, especially the early produced ones from analog tapes, can vary greatly in their volume level, some are pegging their maximum volume and other were released up to -20 dB lower. There is no way to correct for this difference, other than the normal volume controls.
2.- iPod volume - recommended setting is to first disconnect the iPod from the connector, set the volume to "8" and Set the EQ to "POP". This will help the output preamplifiers of the iPod by not overdriving them (such as at "10") and the EQ "POP" setting is Mercedes own recommendation. Reconnect the iPod.
3.- In the Sound section of the Audio unit, get to Volume and make sure this is on "Boost" (not "Standard".)
4.- At this point switching from the Radio to the iPod (Aux vs CD) should produce equal volume with equal clarity.
5.- If this is NOT the case, or if you think the iPod sounds "muddy" or distorted, or a much lower volume level than the radio, then you will need to look for the iPod amplifier.
Here is a diagram. To check, pull out the bottom of the glove compartment, some like to remove the lower panel, or both. The iPod interface is the long rectangular-aspect box. Here is a photo of the iPod amplifier.
6.- The two cases here are: a) there was no iPod Amplifier included with the iPod Interface installation (should have come included in the cost, make sure they get one from Germany), or b) you have an iPod amplifier, and it is sourced from China, and is of defective manufacture. Get the one from Germany, same part number, a world's difference in quality (hey MB, WTF?) See images in previous post in this thread.

The Standard vs Boost setting is in the normal user menu controlled by the silver rotary knob on the center console: Turn the Audio unit on, and push the CD button on the dash.
On the central display, the bottom row has "Aux - Volume - Sound". Since this part of the thread is about getting the iPod to balance volume-wise with the radio, make sure "Aux" is selected and not the CD.
The next menu "Volume", push the knob and a choice of either "Standard" or "Boost" is available. Choose "Boost". The last section "Sound" has Treble, Bass and Fader shelving.
The object of this exercise is to insure that all elements of the inputs to the Audio system are in their standard configurations, to help determine if there is a deficiency that must be further adjusted in the "secret" menu.
Before changing any of these "secret" settings, for iPod users it is important that other situations, such as an absent or defective iPod Amplifier, are not the cause of low volume.
For those who use an iPod through a minijack and the regular Aux input, the previously mentioned settings of iPod Volume = "8", EQ = "POP" and Volume = "Boost" will insure the iPod is at its optimum level before any other adjustments.

Attached are photos of the Volume section and Boost selection, which is active as shown by the DOT preceding Boost. Please refer to post #18 above. Later there will be a new thread about the Parametric Equalizer and Volume settings, for those interested in exactly how these "secret menu" functions operate and what they can do for you.